amygdala response.pdf

/locate/ynimg NeuroImage 41 (2008) 544–552Amygdala responses to emotional faces in twins discordant or concordant for the risk for anxiety and depression Saskia P.A. Wolfensberger,a,c,? Dick J. Veltman,a,c Witte J.G. Hoogendijk,a,c Dorret I. Boomsma,b,c and Eco J.C. de Geusb,c aDepartment of Psychiatry, Vrije Universiteit medical center, Amsterdam, The Netherlands bDepartment of Biological Psychology, Vrije Universiteit, Amsterdam, The Netherlands cCentre for Neurogenomics and Cognitive Research (CNCR), Amsterdam, The Netherlands Received 24 August 2007; revised 30 January 2008; accepted 31 January 2008 Available online 14 February 2008Background: Functional brain imaging studies have shown deviant amygdala responses to emotional stimuli in subjects suffering from anxiety and depressive disorder, but both hyperactivity and hypoac- tivity compared to healthy controls have been reported. To account for these discrepant findings, we hypothesize that genetic and environ- mental risk factors differently impact on amygdala functioning. Methods: To test this hypothesis, we assessed amygdala responses to an emotional faces paradigm during functional magnetic resonance imaging in monozygotic twin pairs discordant for the risk of anxiety and depression (n=10 pairs) and in monozygotic twin pairs concordant for high (n=7 pairs) or low (n=15 pairs) risk for anxiety and depression. Results: Main effects (all faces vs. baseline) revealed robust bilateral amygdala activity across groups. In discordant twins, increased amygdala responses were found for negatively valenced stimuli (angry/anxious faces) in high-risk twins compared to their low-risk co-twins. In contrast, concordant high-risk pairs revealed blunted amygdala reactivity to both positive and negative faces compared with concordant low-risk pairs. Post-hoc analyses showed that these findings were independent of 5-HTTLPR genotype. Conclusions: Our findings indicate amygdala hyperactivity in subjects who are at high risk for